Confusing the Senses
Dr. Calvert explains that many plants defend themselves by confusing herbivores, like monarchs.

"In general, plants tend to grow in groups called 'guilds.' That is, certain plant species are often found grouped together. Scientists think that these guilds might serve to protect individual plants. Here's how: Together, the different kinds of plants produce a mixture of plant odors. The herbivore can't find the correct host because there are too many confusing odors. This would explain why monarchs need to use a combination of senses."